To me, lucid dreaming comes naturally. Once you're dreaming, if you touch something, get hit, feel that something's odd, or any other thing of the sort, yet you feel nothing (not even pain), it's a clear sign that you're dreaming, turning your normal dream into a lucid dream. I've stumbled into lava pools, jumped so high that I pass the clouds, have powers like in the old "DragonBall Z" cartoons, and more of the sort of thing.

I personally believe that lucid dreaming has a LOT to do with self-worth and self-esteem levels, since if you believe that you'll never have a lucid dream, you're bound to never have a lucid dream, no matter how hard you try (unless some external source helps you out somehow).

One thing that allows me to not be scared of nightmares when I'm having one (even while normally dreaming) is that I couldn't care less if I lived or died... And I developed that out of the hundreds of nightmares I had as a kid... I used to always end up dying in many different ways (melting in lava, eaten by birds/tigers, stabbed or shot by gangsters, killed by an alien, gravity gets stronger and i can't run out of the middle of a truck's path, etc)... They kept coming and coming until I taught myself how to wake up from a dream... I closed my eyes and either: (1) If I wasn't lucid dreaming, the first thing I did when a bad situation came up was close my eyes and count to 10, and before I finished the countdown, I was awake; (2) if I was lucid dreaming, I imagined a "Start Menu" popping up, then choosing "Exit", and that took me out of my dream immediately... And the best part was: I always woke up after about 7-8 hours of sleep!

Now it's normal for me to lucid dream at least 3 times a week... Although I have to admit, ever since I was recommended to take multivitamins and fish oil pills for the fatty acids, I've had less lucid dreams, and more dreams showing me what my worries were, and more senseless dreams. My LAST and ONLY nightmares that I have had in probably 8+ years, was (1) around 1-2 months ago, where that my previous girlfriend went back together with her ex and she couldn't get married unless I said "Yes", and (2) me, her and her ex had a class together and she was always making out with him in the chair right behind me (and my vision was in third person)... And yes, I still love her, and we didn't break up because of fighting or whatever, so the connection might still be there. And seeing her with her ex together again would break my heart... And I can't do anything about it because I changed colleges for a year...

Weird enough, though, my dreams now are pretty empty and lacking of sense... I remember one dream was that I started in front of a candy machine, and that whatever snack I wanted I could have for free, so I just stood there pressing buttons, and that was it. Other dreams I have end up waking me with physical effects, but I won't go into that, and it's not sexual or bed-wetting effects.

So yeah... I told you my previous experiences and advice on how to handle your nightmares, so maybe your friend can try them? If he thinks about them everyday and remembers to think about them a lot right before going to sleep, he might never forget about them, and save himself a bad nightmare experience!